A Heating, Ventilation, and Air Conditioning (HVAC) system for a vehicle, may include a first coolant line passing through a radiator; a second coolant line passing through an indoor air conditioning core and a high voltage battery core; a first coolant exchange line passing through a first heat exchanger; a second coolant exchange line passing through a second heat exchanger; a refrigerant line including the first heat exchanger, the second heat exchanger, and a compressor, in which coolant circulates; and a controller configured to control the first valve and the second valve to selectively connect the first coolant line or the second coolant line to the first coolant exchange line or the second coolant exchange line.